The present invention relates to a hybrid orthodontic bracket system and method. More particularly, the present invention relates to an apparatus and method for improving orthodontic bracket and archwire techniques by combining the capabilities of most current and popular edgewise appliance (bracket) designs and corresponding methods and techniques into a single appliance system. This is achieved by cutting, casting, molding, or by other methods of manufacturing bracket slots, stems and/or bases with the appropriate torquing angles, tipping angles, in-out compensations, rotational adjustments and slot dimensions to be used in conjunction with various types and diameters of archwires which will require little or no bending by the operator. The aforementioned preadjustments built into the bracket system, which is directly bonded or banded to the crowns, will, when combined with the force and resiliency of a preformed archwire, direct the crowns into predetermined positions which will represent the various methods and techniques of most current and popular techniques practiced by individual operators.
Early edgewise appliances incorporated very few or no built-in preadjustments and required that crown movement be achieved by placing complex bends into archwires by individual practitioners. The term "edgewise" refers to an orthodontic bracket with a rectangular archwire slot designed so that a square or rectangular archwire has to be inserted with its long dimension placed horizontally into the bracket slot. This "wire bending" procedure led to difficulty in treatment, particularly in the areas of time expended per patient and in the reproducibility of results. In response to these difficulties along with the inconsistencies he observed in treatment results among his peers, Dr. Lawrence Andrews developed the first fully preadjusted and integrated appliance system based upon the crown and occlusal relationships of 120 non-orthodontically treated "normal" dentitions. Preadjusted systems essentially have all necessary angles and planes of movement manufactured directly into the bracket which, when properly placed on the crown, eliminates or greatly reduces the need for wire bending by the operator to achieve desired crown movements. These angles are commonly referred to as "tip", "torque", "in-out" and "anti-rotation." These so-called "straight-wire" appliances would, in effect, allow the memory of unbent archwires to work with the preadjustments to guide teeth into ideal positions. Tremendous professional acceptance and commercial success of the straight-wire appliance led to the development and manufacture of various competitive bracket system designs. All these designs propose various treatment techniques, methods, or philosophies that distinguish systems from one another, particularly in the preferred torque preadjustments.
As more clinicians and manufacturers became involved in the use and design of preadjusted bracket systems, various new techniques and systems were developed. These developments were expressed in appliance design by the selection of various torques, tips, in-outs and anti-rotations that varied from the original Andrews designs. These new designs are essentially various methods for achieving largely uniform and agreed upon goals, best outlined in Dr. Andrews article "The Six Keys to Normal Occlusion." These general goals are proper molar relationships, crown angulations (tip) and crown inclinations, absence of rotations, tight contacts between teeth and a level or slight curve of Spee. For example, Dr. Ronald Roth, while expressing support for Andrews' conclusions, nonetheless determined that overcorrection in most places of movement is the best method for achieving these goals and subsequently designed a "straight-wire" appliance containing these overcorrections. Differences between systems are generally highlighted to promote an exclusivity of design allowing for claims of a proprietary edge in the marketplace. Closer examination shows that the differences between various systems in many preadjustments is not substantial due to goal uniformity. Tip and in-out preadjustments have, in fact, become so uniform as to create little difference between systems. Torque, however, has remained highly variable between systems.
Currently, preadjusted appliance systems are largely technique specific and allow the operator little opportunity to practice techniques promoted by other, mostly nationally known, appliance developers. Differences between systems are usually highlighted by clinicians and manufacturers to promote an exclusivity of the technique and corresponding bracket system thus allowing for claims of a proprietary "edge" in the marketplace. As no single treatment method or system holds all the answers for each individual patient (as evidenced by all the various bracket systems and complimentary techniques), practitioners become "locked in" to a single or limited treatment philosophy. Patient needs can vary widely in individual practices. Specific appliance designs appear to work more efficiently in certain case types, while not as well in others. For example, Ricketts-type practitioners often find this appliance most effective for young children without full permanent dentition when practicing "two-by-four" therapy, while Roth-type practitioners can obtain Andrews ideal crown positions more easily with the common 0.019.times.0.025 rectangular finishing wire. Mixing competitive bracket systems and techniques within private practices is largely unknown and resisted by doctors and staff due to the difficulties in efficiently managing the variables this would present. In addition, several different types of bracket systems would have to be stored in inventory adding substantially to overhead cost.
An object of this invention is to offer an appliance system that combines the potential of all major systems into one "hybrid" appliance system. The hybrid bracket system of the present invention, then, is not a new technique but rather a slot design (as expressed in the brackets by selections of various tips, torques, in-out compensations, rotational compensations, and slot dimensions) that allows practicing most major orthodontic techniques with one appliance design. It is in this way that it has its greatest utility for the operator.
One advantage of the present invention is that nearly any orthodontic technique or mechanical sequence available or recommended from all currently available and popular bracket systems can be performed with the single hybrid bracket system.
Another advantage of the present invention is that the orthodontic procedures that are by far the most popular (Roth, Andrews, Alexander Mechanics) can be performed on less than full sized archwires while still delivering the necessary torques. Full size wires (equal in width to the slot width of the bracket) are often difficult to fit into bracket slots unless the slots are in perfect alignment. This is most often not the case due to limitations in human ability to visualize and place brackets so perfectly, along with variations in crown anatomy which makes this task further improbable or impossible. Most clinicioners, then, will not follow the mechanical sequence recommended by most developers due to the inability to "fill" the bracket slot with full size wires. Even if attempted, achieving the "ideal" or recommended finishing torque positions, as outlined by appliance developers, may be impossible given deviation angles necessary to place "full-size" wires into bracket slots. In other words, some "play" must be necessary just to insert the wire into the slot, leading to less than full expression of built-in torques. Andrews, in fact, recommends against the use of full-sized rectangular finishing wires, which is surprising given his stated goals but understandable given the difficulties in doing so. Wire "rounding" due to the inability to manufacture perfectly square or rectangular archwires also dramatically reduces the actual torque delivered, further reducing the ability to reach stated torquing goals. The use of full size wires is not generally necessary with the hybrid bracket system to achieve "ideal" or recommended torques outlined by major clinicioners. Wire rounding effects may also be compensated for given the available option of selecting a larger finishing wire.
Still another advantage of the present invention is that the less than full sized wires will not express the leveling, tip, and axial (torque) positioning errors as dramatically as full sized wires. Extensive and varied published data, in fact, often recommends against filling the bracket slot in order to avoid the unintended effects of clinically expressing the errors in placement.
Still another advantage, less than full sized wires can deliver less overall force, due to smaller diameters and heightened torque built into the appliance, and can thus be introduced earlier in treatment with lesser fears of damage to the dentition and root structure while providing the same levels of torque correction.
A further advantage of the present invention is that a 0.016.times.0.016 wire (generally considered the smallest potential edgewise starting or finishing wire) will be at the passive borderline of the torque range in the hybrid bracket system. No correction will be delivered, but the bracket and crown will also not be allowed to "drift" excessively into an undesirable position before slot/wire "binding" takes place. In some known techniques and bracket systems, the 0.016.times.0.016 wire will deliver high amounts of torque, while in other systems, this wire will fit so loosely in the slot as to allow much wire "play" and potential for crown drifting. This 0.016.times.0.016 wire is the beginning point in the hybrid system at which torque delivered can steadily and incrementally rise up to full or desired expression.
Most competitive orthodontic appliance systems allow for positive or negative torque cuspids, but not both. The torque choice reflects a treatment philosophy that is quite specific, and would not allow for crossover among or between systems. The hybrid bracket system of the present invention allows an operator a choice between either positive or negative torque cuspids, dependent on patient considerations.
Various torque choices are also available for the bicuspid brackets, which would depend on the actual torque the operator wishes to express along with archwire choice. For example, current 0.022 Roth systems with a popular 0.018.times.0.025 finishing wire choice would deliver no torque in the upper bicuspids. The hybrid bracket system of the present invention offers the same torquing choice in the anterior segment (on smaller wires) and allows the doctor to add bicuspid torque by substituting the more common -7.degree. torque bracket with the hybrid -11.degree. torque bracket. Bicuspids are reversible between arches, and a vertical slot is built in to accommodate hooks for elastics.
The hybrid bracket system of the present invention advantageously provides a distinct upper and lower cuspid bracket for bicuspid extraction cases. Most competitive systems demand that extraction and non-extraction procedures, which vary dramatically in mechanical considerations, be done on the same type of cuspid brackets. To enhance the mechanical demands of retracting the cuspids into open bicuspid extraction sites, tip is increased, torque is lessened and anti-rotation added. A vertical bracket slot is added to allow insertion of a specifically designed hook for attaching elastics.
An additional advantage is that, for all the versatility provided by the system, only seventeen brackets need be manufactured or inventoried to obtain all the capabilities outlined. This number of brackets is comparable or less than other, less versatile, systems. For example, the "A" Company Roth Mini-Twin appliance requires 18 individual brackets and does not include a separate extraction-series bracket for the cuspids.
Creating a bracket system that combines the abilities of most known appliance systems into one hybrid appliance appears to be impossible with the highly variable nature of torque preadjustments between systems. Tip, in-out and anti-rotation, however, are generally expressed uniformly no matter what slot or archwire is employed, and these angles are largely uniform and agreed upon. For example, a 5 degree tip angle placed in a bracket will be expressed evenly no matter if the bracket is an 0.018 or 0.022 slot and generally with little regard to the size or type (round or rectangular) of archwire used. With torque, two other variables will greatly determine how the "built in" preadjustment will perform. These variables include the archwire size and the slot diameter. These two variables combine to determine actual torque values. For example, a +12 torque preadjusted bracket with an 0.022 slot and a 0.019.times.0.025 archwire will create an actual torque of only +4.75.degree.. Changing the slot to an 0.018 width and placing a 0.016.times.0.022 wire in the +12.degree. preadjusted bracket slot creates an actual torque of +6.60.degree.. So, when it comes to the torque component, whatever is built in is modified by the combination of slot diameter and size of the selected archwire. Wire is an important variable, as doctors have access to a large variety of square and rectangular archwires. Built-in torque and slot choice is ultimately more important as they dictate the available range of axial movement (torque). Brackets also cannot be changed or substituted nearly as easily or cost effectively as may archwires.
As discussed above, the bracket system of the present invention allows for most popular, currently available torques to be expressed in one hybrid appliance design when matched with the appropriate square or rectangular archwires. This, in combination with the other currently accepted and largely uniform tips, in-outs and anti-rotations, allows substantially all known methods and techniques to be practiced on one appliance. (It should be noted that no clinician expects the tips, torques, and in-outs to be perfectly identical to any competitive design. Preadjusted systems, as discussed, are by nature not exacting as they are based on averages of non-orthodontic normals. Two degree variances are considered well within the acceptable range.)
In the present invention, instead of a conventional 0.018 or 0.022 bracket slot width, the hybrid bracket system incorporates an 0.020 bracket slot width into each bracket. Various torques can be systematically created for each individual bracket that can replicate any existing system through the choice of the appropriate archwire, while maintaining an integrated "straight-wire" philosophy. The range of available torques in this system, then, would be a key to its flexibility and would separate it from any other commercially available bracket system. The commonly employed tips, in-outs and anti-rotation would also be combined with these torque preadjustments.
The upper and lower non-extraction cuspid brackets are designed to be reversible without affecting angulation but reversing the torque. Some bracket systems call for either positive or negative torque on the cuspids, and this reversibility without affecting angulation or in-out maintains the all encompassing nature of this appliance. A vertically slotted bracket would allow for the insertion of a hook device for attaching elastics after the choice of a positive or negative torque has been made. Proportionality in and between systems can be maintained or enhanced with the hybrid through proper bracket choice. This concept relates to the amount of torque variance between central and cuspid brackets. For example, although the Hilgers/Ricketts formulas are substantially different in torque generation from the Andrews prescription, they contain 16.degree. and 15.degree. torque differential central to cuspid, respectively, which is highly uniform.
An accurate and detailed analysis of actually expressed torques is provided with this system. This is not available in any other systems, largely due to their technique sensitive nature. Many operators of competitive systems are assumed to be expressing the full built-in torques, or are following a highly uniform mechanic sequence to obtain uniformity of results.
In order for brackets with preadjustments to work in union and harmony with one another, bracket placement must be accurate and precise, not only for individual brackets on crowns, but relative to one another. It is known and documented that placing brackets higher or lower vertically on crowns will affect actual torque generation. If placed higher or lower uniformly bracket to bracket, this phenomenon can be more easily managed. If brackets, however, are placed higher or lower relative to one another, the built-in preadjustments, designed to be systematic and interrelated, begin working in disharmony.
To facilitate proper placement and expression of bracket torques relative to one another, the system should include a mesial-distal (horizontal) line etched, painted, cast, molded or otherwise on the bracket or bonding pad or welding flange to determine the "coplanar" level slot lineup. Due to the angled torque preadjustments, the slot opening at the bracket face point often gives a misleading impression of level slot lineup, as the slot bottom (hidden from clear view) may lie on a different plane. The line on the bracket, flange or pad should identify the slot base point, represented by the horizontal line, thus allowing for slot base points to be accurately aligned verses the more inaccurate slot face points. This can be joined with the more common long axis bracket/pad lines (designed to correctly express tip preadjustments) to create a "crosshair" effect, thus heightening the ability to correctly place, and correctly express, built-in bracket preadjustments.
This hybrid orthodontic bracket system of the present invention is not a new technique, but rather a vehicle for incorporating substantially all known orthodontic techniques into one appliance design. It is in this way that it has its greatest utility for the operator.
According to one aspect of the present invention, an orthodontic bracket system includes a plurality of rectangular wires having a plurality of different sizes, and a plurality of brackets including an upper bicuspid bracket, an upper cuspid bracket, an upper lateral bracket, an upper central bracket, a lower bicuspid bracket, a lower cuspid bracket, and a lower anterior bracket. Each of the plurality of brackets is formed to include a 0.020 inch slot for receiving a selected one of the plurality of rectangular wires therein. The slots are aligned at predetermined torque angles to facilitate the practice of nearly any orthodontic technique or mechanical sequence available or recommended from all currently available and popular bracket systems on the hybrid bracket system of the present invention.
In the illustrated embodiment, the upper central bracket includes means for applying any actual torque force to an upper central tooth in a range of actual torque forces from about 0.degree. to above +10.degree. to an upper central tooth. The upper lateral bracket includes means for applying any actual torque force to an upper lateral tooth in a range of actual torque forces from about 0.degree. to above +6.degree. to an upper lateral tooth. The upper cuspid bracket includes means for applying any actual torque force to an upper cuspid tooth in a range of actual torque forces from above -4.degree. to above +4.degree. to an upper cuspid tooth. The upper bicuspid bracket includes means for applying any actual torque force to an upper bicuspid tooth in a range of actual torque forces from about 0.degree. to below -5.degree..
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived. For example, individual operators have a defined and verifiable method for creating their own specific technique or system that falls in the intermediate ranges of torque available, which can vary patient to patient depending on individual case types and requirements. It should be noted that there is no officially sanctioned or preferred method for treating cases orthodontically.